1. Field of the Invention
This invention relates to an apparatus for determining the amount of air and other non-condensable vapors that are collected along with liquid and vapor refrigerant in a storage container of a refrigerant recovery unit.
2. Description of the Prior Art
Because of the present environmental concerns due to the fluorocarbons found in most refrigerants, the collection and recycling of refrigerant has become a very important practice. This creates a need for collecting refrigerant from refrigeration systems in appropriate containers so that the refrigerant may be properly recycled. When refrigerant is collected from a refrigeration unit, air and other non-condensable vapors also collect in the storage container. These non-condensable vapors may collect and build up in the storage container so that the container must be vented off or purged.
There are a variety of different purge systems that have been used in refrigeration storage units. These usually involve some type of purge valve that is connected to the container where non-condensable vapor from a condenser or some other component of the refrigeration system builds up. As the amount of non-condensable vapor in the container increases, the valve opens causing the non-condensable vapors to be vented off.
A variety of methods are used to determine when the vapors should be vented. A common method involves measuring a pressure differential between the container and the atmosphere. The container is vented when this pressure differential reaches a predetermined point. Some purge systems measure the saturated vapor pressure of a permanently sealed refrigerant sample that is brought to the temperature of the refrigerant where the non-condensable vapor builds up, such as a storage container. A pressure differential is then measured between the container and the sample. When the pressure exceeds a predetermined amount, the container is vented. Other methods involve measuring time, temperature, fluid levels, flow rates or other variables that would indicate how much non-condensable vapor has built up.